The present invention is directed to improvements in flying shear apparatus, particularly, but not necessarily, of the type described and claimed in the Dolle U.S. Pat. No. 3,869,949, granted Mar. 11, 1975 to Aetna-Standard Engineering Company, of Elwood City, Pennsylvania. The flying shear apparatus described in the before-mentioned patent is designed and intended particularly for severing moving metal strip or sheet material. To this end, the shear mechanism includes a moveable carriage, which mounts opposed shear blades, and which is arranged to be advanced in the direction of, and at the same rate of speed as the moving strip material, throughout a short distance. When it is desired to sever the strip, the shear carriage is accelerated up to the speed of the strip and momentarily moved in synchronism therewith. During the moments of synchronous movement, the shear blades are actuated to sever the moving strip in the desired manner. The shear carriage is then returned to its starting position in preparation for a subsequent severing cycle.
In flying shears of known design, provisions have been made for supporting the cut leading edge of strip, as it leaves the shear carriage, in order that the leading edge may be properly guided to a subsequent stage of the handling or processing equipment. Such known provisions include a retractable conveyor system, as shown in the before-mentioned Dolle U.S. Pat. No. 3,869,949. Insofar as is known, however, prior systems have not provided appropriate means for the support of the strip material on the upstream or entry side of the shear carriage, such that a progressively increasing length of the strip material becomes unsupported as the shear carriage is traversed in the direction of strip movement during a shearing operation. In other words, with the shear carriage in its initial or upstream position, adequate conventional provisions can be made for the support of the incoming strip. However, as the carriage is accelerated and moved in a downstream direction along with the strip, in order to effect a severance thereof, a constantly lengthening span of unsupported strip material is accumulated between the shear carriage and the fixed strip supporting means at the incoming side of the equipment. Such a condition is acceptable when the strip material is adequately stiff and/or speeds of strip movement are relatively low. However, for thinner gage material, such as strip on the order of 0.007 inches in thickness, which may be processed at speeds in excess of 300 feet per minute, a substantial unsupported span of material may cause significant handling problems.
In accordance with the present invention, novel and advantageous means are provided for supporting strip material on both the upstream and downstream sides of a moving shear carriage, such that the support of the strip material remains constant even as the shear carriage is in motion.
Pursuant to the invention, a flying shear apparatus is provided with a novel form of strip supporting conveyor system, in which driven conveyor belt means are guided in part by a plurality of guide sheaves carried by the moving shear carriage. The arrangement of the moving guide means is such that driven strip-supporting conveyor elements are guided up to the shear carriage in the support plane or pass line of the strip material, then guided around underneath the carriage, and then returned to the support plane for the strip material on the immediate downstream side of the shear carriage. The shear carriage mounts a plurality of such guide sheaves, so arranged that the relationship of the conveying and supporting elements to the shear carriage remains constant, regardless of the position of the carriage, and this is achieved by guiding the conveyor-supporting elements underneath the carriage, using guide means mounted on the carriage itself and moveable therewith.
In the system of the invention, normally fixed strip supporting means are provided at the upstream and downstream sides of the shear carriage, and a novel intermediate support extends between the normally fixed means. The intermediate support has a constant effective working length and a constant relationship to the shear carriage, but varies with movements of the carriage. The arrangement is such that the intermediate support simultaneously lengthens on one side of the carriage and contracts on the other as the carriage moves.
For a more complete understanding of the above and other features and advantages of the invention, reference should be made to the following detailed description and to the accompanying drawings.